Electronic data such as multimedia content (MM) is routinely transmitted from a server to a client over a network. A receive buffer within the client functions to accommodate the differences between the transmission rate of the electronic data between the server and the client and the consumption rate of the electronic data at the client. The receive buffer empties during periods when the consumption rate of the electronic data is higher than the transmission rate and fills when the consumption rate is lower than the transmission rate.
Typically, prior to the presentation of the electronic data at the client, the receive buffer is filled with electronic data. If the receive buffer is depleted during the presentation of electronic data, disruptions in the presentation of the electronic data will occur. The amount of data within the receive buffer (referred to herein as the buffer fill level) may be affected by network conditions and/or the consumption rate of the electronic data at the client. Network conditions, especially in home wireless networks, change as a function of time, thereby varying the transmission rate of the network. Additionally, in variable bit rate (VBR) streaming systems, the consumption rate of the electronic data at the client varies as a function of time as well.
Two known approaches for transmitting data to avoid depletion of the receive buffer include an averaging transmission system and a buffer fill level feedback system. In an averaging transmission system, the server transmits data at an average transmission rate based on the average bit rate for the entire electronic data file. In a buffer fill level feedback system, the client informs the server when the buffer is above a high fill level or below a low fill level. The server then transmits at a higher rate when the buffer is below a low fill level and at a lower rate when the buffer is above a high fill level. In both of these approaches, a relatively large receive buffer is necessary to guard against depletion of the receive buffer. The use of a relatively large receive buffer, however, increases the size and cost of the client, thus affecting adversely portability and profitability.
Accordingly, methods, systems, and apparatus are needed to alleviate the impact of VBR streaming and bandwidth variations on performance that are not subject to the above limitation. The present invention fulfills this need among others.